Question

Given this unit circle what is the value of x

Answer 1

`x=-(√(51))/(10)`

Explanation:

You want the value of x in the third quadrant of a unit circle where y = -7/10.

Pythagorean theorem

The radius of a unit circle is 1, so the Pythagorean theorem tells you the magnitude of the value of x is ...

1² = x² +(7/10)²

x = -√(1 -49/100) = -√(51/100) . . . . . . x < 0 in the third quadrant

x = (-√51)/10